parks victoria technical series marine natural values study vol 2 ...
parks victoria technical series marine natural values study vol 2 ...
parks victoria technical series marine natural values study vol 2 ...
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Parks Victoria Technical Series No. 79<br />
Flinders and Twofold Shelf Bioregions Marine Natural Values Study<br />
2.2.3 MARINE ECOLOGICAL COMMUNITIES<br />
General<br />
Since the first <strong>natural</strong> <strong>values</strong> report by Plummer et al. (2003) there has been limited further<br />
research or mapping surveys in Ninety Mile Beach MNP. There has been broadscale<br />
bathymetric mapping, with the intertidal and shallow subtidal areas mapped by aerial LiDAR<br />
surveys. There have been no surveys of the pelagic habitats.<br />
No new surveys of biota have been done in the MNP since declaration. Our knowledge of<br />
biota found in Ninety Mile Beach MNP is limited to large fauna such as birds and mammals<br />
(Appendix 1). Forty-nine species of birds and over six species of <strong>marine</strong> mammals have<br />
been recorded in or in the immediate surrounds of the MNP.<br />
Intertidal<br />
Soft sediment<br />
The intertidal soft sediment is in the north of Ninety Mile Beach MNP as a high-energy steepfaced,<br />
coarse-grained sandy beach fronting an extensive dune barrier system. The intertidal<br />
sand communities at McGaurans and Woodside Beaches to the west of the MNP are<br />
species-poor (LCC 1993). Between 1983 and 1990 eight surveys were conducted at these<br />
beaches and found low biodiversity (nine species per sample) and dominated by isopods,<br />
with bivalves, polychaetes, amphipods and insect larvae (LCC 1993). Bivalves (such as<br />
pipis) and worms are known to occur in the sand in the lower intertidal area (LCC 1993).The<br />
abundance of beach infauna was also low (5 to 102 m 2 ), with invertebrate populations on<br />
both beaches being extremely variable, fluctuating considerably between years. This is<br />
typical of these types of beaches.<br />
Flora is restricted to macroalgae drift and macroalgal epiphytes. Beach-washed materials in<br />
sandy beach habitats are a significant source of food for scavenging birds, and contribute to<br />
the detrital cycle that nourishes many of the invertebrates, such as bivalves, living in the<br />
sand.<br />
Reef<br />
There is no intertidal rocky reef in the Ninety Mile Beach MNP.<br />
Subtidal<br />
Soft sediment<br />
Invertebrate species diversity of subtidal soft sediment in the Orbost region at the eastern<br />
end of Ninety Mile Beach is regarded as one of the most biologically diverse <strong>marine</strong><br />
environments in the world (Coleman et al. 1997). Invertebrate diversity in East Gippsland<br />
was therefore higher compared to the rest of the Victorian coastline and was generally<br />
greater with depth (Coleman et al. 2007; Heislers and Parry 2007). A transect east of the<br />
MNP was sampled with 0.1 m 2 grab samples in 10 and 40 m of water depth. The shallow<br />
sediment was fine sand and deep was medium sand (Coleman et al. 2007). The grab<br />
samples contained between 260 to 430 individuals and 36 to 72 species (Coleman et al.<br />
2007). Crustaceans were the dominant taxa in both depth classes, representing more than<br />
13 of the 21 most abundant families (Heislers and Parry 2007). Ten families were common<br />
in both depth classes (Heislers and Parry 2007). These organisms live in or on the sand and<br />
their ecological relationships are poorly known, except that they are a key component of the<br />
local food web and that their population dynamics are extremely variable (Parks Victoria<br />
2006e).<br />
No information on nearshore fish is available from within the MNP, but recreational fishing<br />
guides indicate that Seaspray Beach, (just east of the MNP), is known for populations of<br />
Australian salmon Arripis sp., snapper Pagrus auratus, tailor Pomatomus saltatrix and<br />
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